Bicycle seat

ABSTRACT

Among other things, a compliant element is configured to attach a seat of a device on which a user pedals to a frame of the device. The compliant element has a stiffness that is small enough to permit substantially unimpeded rocking of the seat relative to the frame in a plane in which the spine and pelvic bone of the user lie when the user is on the seat, and is large enough to maintain the seat in a substantially horizontal plane when the user is not on the seat.

This application relates to U.S. patent application Ser. No. 13/675,864filed on Nov. 13, 2012 and incorporated by reference here in itsentirety.

BACKGROUND

This description relates to a bicycle seat.

Hominids, particularly the fatuously self-designated Homo Sapiens, mayachieve locomotion over dry land in a variety of ways, of which the mosttypical for an adult, uninjured, non-inebriated individual are runningand walking. As humans have modified parts of the earth's surface intorelatively smooth pathways for easier walking and running, and haveinvented axles and wheels, the invention of the bicycle has also beenpossible as a way of increasing speed by mechanical advantage.

Viewed ergonomically, pushing pedals in a circle is geometricallysimple, but requires complex articulation to be accomplished through thenon-simple anatomy of a creature evolved for running over non-simplesurfaces. For as long as there have been bicycles it has been evident toeveryone that bicycle saddles (we sometimes use the term seatsinterchangeably with saddles) are uncomfortable. The rider's weight anddiscomfort are on and in the rider's crotch. Attempts have been made torelieve discomfort by hollowing the saddle at the center, whichnecessarily makes the saddle wider and thus increases friction betweenthe rider's inner thighs and buttocks and the saddle. Any increase infriction in any human powered machine is not likely to be a good idea.There seems to be an idea that a cyclist needs to hold on to a bicycleby the seat of his pants, which is left over from the long associationbetween humans and horses. This is largely nonsense. Bicycles havehandlebars.

SUMMARY

In general, in an aspect, a compliant element is configured to attach aseat of a device on which a user pedals to a frame of the device. Thecompliant element has a stiffness that is small enough to permitsubstantially unimpeded rocking of the seat relative to the frame in aplane in which the spine and pelvic bone of the user lie when the useris on the seat, and is large enough to maintain the seat in asubstantially horizontal plane when the user is not on the seat.

Implementations may include one or any combination of two or more of thefollowing features. The compliant element includes a spring. Thecompliant element includes a helically wound spring. The compliantelement includes rubber cylinders. The compliant element is configuredto be attached to connectors associated respectively with the seat andwith the frame. The connector is associated with the seat and configuredto receive a portion of the compliant element. The connector isassociated with the frame and configured to receive a portion of thecompliant element.

In general, in an aspect, a spring has a helical winding, a threadedhole associated with a seat, and a threaded hole associated with theframe, the helical winding of the spring matching the threaded holesassociated with the seat and the frame.

Implementations may include one or any combination of two or more of thefollowing features. The spring is linear and can be tightly wound withno spaces between successive turns or can be more loosely wound withspaces between successive turns. The connector includes the threadedhole associated with the seat. The connector includes the threaded holeassociated with the frame.

In general, in an aspect, a bearing structure between a seat and a frameof a device on which a user pedals includes portions associatedrespectively with the seat and the frame and that can move relative toone another while remaining in contact. The bearing structure isconfigured to permit relatively free rocking motion within a plane thatis perpendicular to the direction in which the user is facing while onthe seat, to permit relatively less rocking motion within a plane thatincludes the spine of the user and the direction in which the user isfacing, and to permit essentially no motion of the seat relative to theframe in the direction of gravity.

Implementations may include one or any combination of two or more of thefollowing features. The bearing structure includes a compliant memberthat exerts a force tending to pull the seat towards the frame. Thebearing structure includes a flat annular surface associated with theframe and a semicircular surface associated with the seat.

In general, in an aspect, a bearing structure between a seat and a frameof a device on which a user pedals includes a flat surface associatedwith the frame and a semi-circular surface attached to the seat, thesemi-circular surface rolling across the flat surface when the user ispedaling.

Implementations may include one or any combination of two or more of thefollowing features. The compliant element tends to return the feed to aresting upright position relative to the frame when the user is not onthe device.

These and other aspects, features, and implementations, and combinationsof them, can be expressed as systems, components, assemblies, apparatus,methods, and means and steps for performing functions, and in otherways.

Other aspects, features, and implementations will become apparent fromthe following description and from the claims.

DESCRIPTION

FIG. 1 is a composite front elevation of a bicycle seat, left sideshowing the transverse beam adjusted to the maximum length, and rightside showing the transverse beam adjusted to the minimum length.

FIG. 2 is a horizontal section through the transverse beam and seats.

FIG. 3 is a vertical section through the transverse beam and the centralball and socket joint and the seat mount bearings.

FIG. 4 is a vertical section 90 degrees across the centerline of thetransverse beam through the central ball and socket joint.

FIG. 5 is a vertical section 90 degrees across the centerline of thetransverse beam through the seat mount bearings.

FIG. 6 is a horizontal section through the upper part of the transversebeam.

FIG. 7 is a plan view of a portion of the seat support.

FIG. 8 is a side elevation of a portion of the seat support.

FIG. 9 is a front elevation of a portion of the seat support.

FIG. 10 is a plan view of a portion of the seat support.

FIG. 11 is a side elevation of a portion of the seat support.

FIG. 12 is a front elevation of a portion of the seat support.

FIG. 13 is a plan view of a portion of the seat support.

FIG. 14 is an elevation of a portion of the seat support.

FIG. 15 is a plan of a portion of the seat support.

FIG. 16 is a plan of a portion of the seat support.

FIG. 17 is an elevation of a portion of the seat support.

FIG. 18 is a plan view of a bicycle with the seat installed.

FIG. 19 is a side elevation of a bicycle with the seat installed.

FIG. 20 is a rear elevation of a bicycle with the seat installed.

FIG. 21 is a side elevation of a pelvic bone and buttock seated on theseat as it would appear with the near pedal at 2 o'clock position.

FIG. 22 is a rear elevation of a pelvic bone and buttocks seated on theseat as it would appear with the right side pedal at 2 o'clock position.

FIG. 23 is a plan view of a pelvic bone seated on the seat as it wouldappear with the right side pedal at 2 o'clock position. Arrows drawnthrough the femur sockets of the pelvic bones show how these axes gyratein sympathy with and remain parallel to the transverse beam of the seat.

FIG. 24 is a matrix of views of the bicycle seat at four different pedalpositions as a means of illustrating how the seat articulates its waythrough a pedaling cycle. The four positions are identified (from top tobottom) as the angle of the pedal crank arms as compared to theidentical angles of the hour hand of a clock. Starting from the top andproceeding toward the bottom in the first column, the angles taken asexamples of pedal positions are as at 2 o'clock, 5 o'clock, 8 o'clock,and 11 o'clock. The seat is illustrated from left to right on the pageas a right side view, a rear view, and a top view. The matrix of viewsis formed as each pedal angle is illustrated in each view. Throughoutthe pedaling cycle, in every case, a line drawn through the sockets ofthe pelvis which hold the upper ends of the femurs will remain parallelto the transverse beam of the seat. Thus the seat allows the pelvis tomove freely without constraint as it would in running.

FIG. 25 is a horizontal section through transversely perforated blockand assembled transverse beam shown at maximum and minimum extensions.

FIG. 26 is a front elevation of the bicycle seat with the transversebeam shown at maximum and minimum extensions.

FIG. 27 is a side elevation vertical section through the transverselyperforated block and the assembled transverse beam.

FIG. 28 is a front elevation of a portion of the seat support.

FIG. 29 is a plan of a portion of the seat support.

FIG. 30 is a side elevation of a portion of the seat support.

FIG. 31 is a front elevation of a portion of the seat support.

FIG. 32 is a side elevation of a portion of the seat support.

FIG. 33 is a plan of a portion of the seat support.

FIG. 34 is a plan of a portion of the seat support.

FIG. 35 is a front elevation of a portion of the seat support.

FIG. 36 is a front elevation vertical section through the centralbearing showing parts 214, 216, 310, 220, 224, 226.

FIG. 37 is a side elevation vertical section through the central bearingand the assembled transverse beam.

FIG. 38 is a horizontal section through the lower part of the centralbearing.

FIG. 39 is a composite front elevation of a bicycle seat, left side,showing a transverse beam adjusted to the maximum length, and right sideshowing the transverse beam adjusted to the minimum length.

FIG. 40 is a front elevation of the right end of the bicycle seat,showing the seat structure tilted toward the transverse beam part 28,and showing how the seat mount 36 does not contact the transverse beamin this tilted position because of cut out 62.

FIG. 41 is a side elevation of the bicycle seat showing the seatstructure in a forward tilted position and showing how the seat mount 36does not contact the transverse beam part 28 because of cut out 62.

FIG. 42 is a front elevation vertical section through the centralbearing showing parts 312, 314 connected by a coiled spring 310.

FIG. 43 is a side view of the assembly of FIG. 42.

FIG. 44 is a vertical section through part 312 shown in FIG. 42.

FIG. 45 is top view of part 312 shown in FIG. 42.

FIG. 46 is a modified version of FIG. 8, with post 14 modified to fit insocket 316 of FIG. 42.

FIG. 47 is a front is a front elevation of part 313 shown in FIG. 42.

FIG. 48 is a side elevation of part 314 shown in FIG. 42.

LIST OF PARTS

-   10, seat post shaft-   11, shaft upper end-   12, cantilevered beam-   14, vertical post-   16, central joint ball-   17, plan view centerline of rectangular split block 19-   18, central socket, forward half-   19, rectangular split block-   20, central socket, aft half-   21, channel-   22, bolt, nut, washer, left side-   23, 25, split block bolt holes-   24, bolt, nut, washer, right side-   26, transverse beam, left side-   28, transverse beam, right side-   29, beam holes-   30, transverse beam end post and ball, left side-   32, transverse beam end post and ball, right side-   34, seat mount socket, left side-   36, seat mount socket, right side-   38, seat part, left side-   40, seat part, right side-   42, seat upholstery, left side-   44, seat upholstery, right side-   45, 47, split block edges-   49, 51, vertical post outer surfaces-   60, 62, transverse beam cut outs-   63, 64, tilting of the seat parts-   66, hole in vertical post 14-   68, bungee cord-   70, hole in transverse beam end-   72, knot in bungee cord 68-   74, hole in transverse beam end post-   76, bungee cord-   78, hole in seat mount socket-   80, knot in bungee cord 76-   112, cantilevered beam or spring-   114, transversely perforated block-   115, opening in block 114-   116, transverse beam, left side-   118, transverse beam, right side-   120, transverse beam end post and ball, left side-   122, transverse beam end post and ball, right side-   124, cheek piece, left forward-   125, rounded end of 124 cheek piece-   126, cheek piece, left aft-   127, rounded end of 126 cheek piece-   128, cheek piece, right forward-   129, rounded end of 128 cheek piece-   130, cheek piece, right aft-   131, rounded end of 130 cheek piece-   132, bolt, nut, washer, left side-   134, bolt, nut, washer, right side-   136, seat mount socket, left side-   138, seat mount socket, right side-   140, seat, left side-   142, seat, right side-   210, seat post shaft-   212, cantilevered beam or spring-   214, vertical post-   216, short cylinder with recessed top and central hole-   217, central hole in short cylinder 216-   218, array of rubber cylinders-   219, shallow holes arranged in circle in short cylinder 216-   220, short cylinder with recessed bottom and central hole-   221, central hole in short cylinder 220-   222, Dacron cord-   223, shallow holes arranged in circle in short cylinder 220-   224, mounting block for transverse beam-   225, vertical central hole in mounting block 224-   226, bolt, nut, washer-   227, knots at ends of Dacron cord 222-   228, transverse beam, forward half-   230, transverse beam, aft half-   310, coiled spring-   312, post connector-   313, post connector part-   314, beam connector-   315, beam connector surface-   316, lower socket of post connector 312-   317 beam connector surface-   318, 319 socket of post connector 312-   320, platform-   322, rockers-   321, bearing surface of the beam connector-   323, beam connector axis-   324, socket of beam connector 314-   325, post connector axis-   326, flat upper portion of beam connectors 314-   327, 329 bearing surface of the post connector

To be good ergonomically, an interface between human and bicycle shouldallow a close (e.g., the closest possible) approximation of the way thehuman skeleton is articulated in the act of running naturally. Thebicycle seat, as a principle part of the human to bicycle interface,should support part of the rider's weight, while not interferingunnecessarily (e.g., by interfering to the least possible degree) withthe natural articulation characteristic of the running body, and withthe flow of blood to and from the rider's legs and feet, and shouldcreate little (e.g., the least possible) friction anywhere in the riderplus bicycle system.

Here we describe a divided and fully articulated bicycle seat that isergonomically designed to support the weight of the rider on his twobuttocks and not constrain the motion of the rider's body in anydirection except the straight down direction (in resisting gravity), andthen only proportionally to the way the weight of the rider isdistributed between the buttocks at a given instant during each pedalingcycle. There are two separated seat parts, each supporting one of therider's buttocks (we sometimes refer to the seat parts as buttocksupports). Each of the seat parts is designed to move and reorientitself freely with the position and orientation of the buttock seated onit, during the pedaling cycle, and not to move at all relative to thebuttock, creating no friction between the buttock and the seat part.

In some implementations, as the rider pedals, a transverse beam on whichthe two seat parts are mounted gyrates through three-dimensional space,following and not resisting at any point in the pedaling cycle thenatural motion of buttocks attached to legs which are driving pedals.The ball and socket joints through which the seat parts are mounted attwo places (e.g., at the ends) of the transverse beam gyrate in sympathywith the beam while a surface of each of the seat parts continuallyreorients itself to maintain a constant orientation relative to thecorresponding buttock. The buttock supporting seat parts of thisstructure, whose mounts allow them to tilt in any direction and rotateindependently from the transverse beam on whose ends they are mounted,maintain constant contact with the lower surfaces of the buttocks andtilt and rotate relative to the transverse beam exactly in sympathy withthe buttocks throughout the pedaling cycle, and thus do not rub againstthem. Therefore no (or as little as possible) friction is createdbetween the rider's skin and this structure. This arrangement ofuniversal (e.g., ball and socket) joints functionally mirrors thearrangement in the human body, in which the pelvic bone is free togyrate relative to the bottom of the spine, and the femurs are free togyrate relative to the ends of the pelvic bone.

As the free flowing action of the seat does not constrain the body inthe act of pedaling (in other words, the femurs and pelvic bone arecompletely free to move and gyrate as they normally do while running),it is also true that it provides the rider's crotch with no way tostabilize or constrain the bicycle. This however is not needed becausethe rider can support herself and control the bicycle with thehandlebars and by shifting her weight on her hands and feet on thehandlebars and pedals. While it is true that riders have traditionallyused saddles to create stability and help steer, the loss of this is asnothing compared to the benefit of the freedom of motion and the loss offriction between the rider and the bicycle of the saddle being describedhere.

Some implementations are illustrated by example in FIG. 1 (a frontelevation of the assembled parts of the seat), and FIG. 2 (a horizontalsection through the plan view of the transverse beam and seats). Asshown in FIG. 39, thin bungee cords of no great strength may be added tothe vertical post 14 and to the transverse beam end posts, left side andright side 30 and 32, to gently return the transverse beam and the seatsections to square and level default positions, when not being pushed bythe rider, to facilitate the act of mounting the bicycle. A thin bungeecord 68 passes through holes 66 and 70 in vertical post 14 andtransverse beam end posts 30 and 32, and is fixed in place under lighttension by knots 72, typical. Two other bungee cords 76 pass throughholes 74 and 78 in transverse beam end posts 30 and 32 and seat mountsockets 34 and 36 and are fixed in place under light tension by knots80, typical. The bungee cords may be of thin diameter, ⅛″, for example,and under the minimum tension needed to pull the transverse beam andseat mounts to square and level positions. This tension need only bevery light as the elements of this structure weigh little and are wellbalanced on their mounts. A variety of other devices and combinations ofthem could be used to provide such tension, including curved flat leafcompression springs and coil springs.

As also shown in FIG. 8, in some instances, a seat post shaft 10 is a14″ long (A) cylinder of a diameter which fits inside the seat post ofthe bicycle, and which can be used to adjust the seat height by slidingit into and out of the seat post to the desired height and tighteningthe bicycle's own seat post clamp. The seat post shaft 10 may be made ofaluminum or steel or glass reinforced plastic (GRP) or plastic andcarbon fiber composite, for example. A short (for example, about 3″measured from the centerline of the shaft to the centerline of the post(A₁)) cantilevered beam 12 of the same material, for example, is weldedto, or integrally cast with the seat post shaft 10 at its top end, at anangle of about 115 degrees, such that, with the seat post shaft 10inserted in the bicycle seat post, the cantilevered beam 12 will belevel and extend, cantilevered aft along the centerline of the bicycle,about 3″, so that the rider sitting on the seat will have the samerelative position (fore and aft) to the pedals and handlebars he wouldhave if sitting on a traditional saddle. At its free end thecantilevered beam 12 turns vertical, for example by the same means itpreviously turned horizontal, to form a short vertical post 14, forexample, 1″ from the top of the beam to the bottom of the sphericalfinial (A₂). At its top end, the vertical post 14 is reduced in diameterto ¾″ (A₃) and ends in a 1″ diameter (B) spherical finial 16. If thevertical post 14 is made of aluminum or steel tubing, the central jointball 16 may be made of cast aluminum, or GRP, or composite, or nylon,for example, and made as a separate piece and inserted in the end of thevertical post 14. If the seat post shaft 10, the cantilevered beam 12,and the vertical post 14 are made of GRP or composite, the central jointball 16 may be an integral part of the whole casting. The central jointball 16 acts as the ball of a ball and socket joint which connects theseat post shaft 10, the cantilevered beam 12, the vertical post 14, andthe central joint ball 16, shown assembled in figures land 8, to theassembled transverse beam.

As shown in FIG. 4, for example, a central socket, forward half 18 and acentral socket, aft half 20 are two identical halves of a rectangularnylon block which is split in half along the lengthwise verticalcenterline 17, as also shown in FIGS. 11, 12, and 13. The identicalparts 18 and 20 each measure, for example, 3″ long (G), ⅞″ wide (H), and1½″ high (I), so that, when assembled, split block 19 measures 3″ long,1¾″ wide (J), and 1½″ high. The split block halves 18 and 20 arehollowed to form a spherical socket for which the central joint ball 16forms the ball. A channel 21 (see FIGS. 11, 12, and 13, for example) iscut in the bottom of the assembled block, lengthwise, of a width to passthe ¾″ diameter stem of post 14, and cut increasingly deeply going fromthe ends toward the center. This channel will allow the assembledtransverse beam to rock from side to side relative to the bicycle, butnot to tip forward or aft. This ball and socket joint also allows theassembled transverse beam to rotate on a vertical axis while at anyangle of side to side rocking. The two halves of the rectangular splitblock 18 and 20 have two bolt holes 23, 25, ¼″ in diameter, passingthrough the assembled block horizontally through the verticallongitudinal centerline split. The two ¼″×3″ hex head bolts with nutsand washers 22 and 24, which hold all of the parts of the transversebeam together, pass through these holes. The two halves of therectangular split block 18 and 20 may alternatively be made of aluminum,or GRP, or composite, for example.

The transverse beam has a left side and a right side 26 and 28 thatcomprise two identical flat pieces as shown with dimensions in FIGS. 9and 10. In some implementations, the main flat section is, for example,5/16″ thick, 1½″ high (C), and 4⅜″ long (D). The adjoined section, whichis bent toward the plan view transverse beam centerline 17, is, forexample, 5/16″ thick (F), 1⅜″ long, and reduces in height from 1½″ atthe end joined to the main flat section to 1″ height at the end whichconnects to a ½″ diameter (D1) vertical post with a ¾″ diameter (D2)spherical finial on top with a total height of 2⅛″

. The two sides of the transverse beam 26 and 28 bolted together oneither side of assembled rectangular split block halves 18 and 20 formthe transverse beam which supports and connects the divided seatsections. Two rows of evenly spaced ¼″ diameter holes 29 arrangedrespectively along the two sides of the transverse beam 26 and 28 arebored to align with the two holes in the assembled halves of therectangular split block 18 and 20, such that pairs of holes in the twosides of the transverse beam 26 and 28 can be selected and alignedsymmetrically on either side of the assembled halves of the rectangularsplit block 18 and 20, such that the centers of the seat sections 38 and40 at the ends of the transverse beam are as far apart as the bones ofthe buttocks, (ischeal tubularities), of the particular rider.

All of the figures showing the seat assembled show the left side of thetransverse beam 26 bolted on in its shortest position and the right sideof the transverse beam 28 bolted on in its longest position. In typicaluse, the two parts would be bolted on symmetrically, so the center ofthe central joint ball 16 and the longitudinal center of the assembledtransverse beam align. The ends of the two sides of the transverse beam26 and 28 extending beyond the rectangular split block 19 bend towardthe plan view longitudinal centerline of the transverse beam such thatthe centers of the seat sections and the center of the central jointball 16 align in plan view. The vertical dimension of the two sides ofthe transverse beam 26 and 28 is reduced as they approach theirconnections to two ½″ diameter (D₁) transverse beam end posts 30 and 32,to allow clearance for the seat sections to gyrate freely.

The left side and right side transverse beam end post 30 and 32 are ½″diameter posts that have corresponding ¾″ diameter (D₂) sphericalfinials on top, as shown in FIGS. 9 and 10, for example. These finialsact as the balls for ball and socket joints which connect the respectivetwo seat parts to opposite ends of the transverse beam. The left sideand right side transverse beam end posts and balls 30 and 32 may be castintegrally with left and right sides of the transverse beam 26 and 28,if made of aluminum or GRP or composite, for example.

Left side and right side seat mount sockets 34 and 36 are hollowed nylonblocks, as shown in FIGS. 16 and 17, which act as the sockets which fiton the finials of the transverse beam end posts and balls 30 and 32.Hollowed blocks 34 and 36 are square in plan view and measure 1½″ by 1½″(K), for example. In side elevation they measure 1″ high (L), forexample. The hollowed blocks may pop on or they may be split andassembled around the balls using fastenings or adhesives. They may bemade of aluminum, or GRP, or composite, or cast as integral parts of theseat parts 38 and 40. When mounted on the transverse beam end posts andballs 30 and 32 the hollowed blocks are free to tilt at least about 15degrees, for example, in any direction from a level position, but thehollow blocks serve as stops to prevent tilting of the two seat partsfarther than that permitted amount of tilting.

The two seat parts 38 and 40, shown in FIGS. 14 and 15, for example, aretwo 4″ diameter disks, slightly concave in both horizontal dimensions ontop, and are covered by left side and right side seat upholstery 42 and44. The upholstery may be cotton batting covered with canvas, or foamcovered with plastic, or sheepskin, fuzzy side up, for example. The leftside and right side seat mount sockets 34 and 36 are fastenedconcentrically to the bottom sides of the seat parts 38 and 40 withfastenings or adhesives, or may be cast together with the seat parts 38and 40 as single units. The seat parts 38 and 40 are made of aluminum,or GRP, or composite, or other plastic, for example.

FIGS. 5 and 41 both show a vertical section 90 degrees across thetransverse beam through the seat mounts, showing how the left and rightsides of the transverse beam 26 and 28 are cut away 60, 62, (see alsoFIG. 1) at their outer ends to allow clearance for the seat parts andseat mount sockets to gyrate. FIG. 41 shows a side elevation of seatpart 40 and seat mount socket 36 in a forward tilted position 64, andhow transverse beam cutout 62 allows clearance in this position. FIG. 40is a front elevation of the right end of the bicycle seat, the left endbeing identical, showing the seat structure tilted toward the transversebeam part 28, and showing how seat mount 36 does not contact thetransverse beam in this tilted position because of cut out 62. FIGS. 40and 41 show the seat mount socket passing as close as it ever comes tothe transverse beam in the seat's three-dimensional gyrating path, thusshowing that these parts never come in contact.

FIG. 2 shows a horizontal section through the transverse beam assemblywith its ball and socket joint, ball 16, rectangular split block 19,bolts 22 and 24, and through the balls 30 and 32 and sockets 34 and 36joints of the seat mounts, and shows in outline separated seat parts 38and 40 above the transverse beam assembly. FIG. 2 shows how the elementsof the transverse beam are bolted together, and how pairs of holes canbe selected from the rows of holes in the left side and right sidetransverse beams 26 and 28 to align with the two holes in assembledrectangular split block 19 to create a transverse beam of desiredlength.

FIG. 6 shows a horizontal section through the transverse beam near itstop. This shows how the forward and aft halves of the central socket 18and 20 are split on their longitudinal vertical centerline and how thebends in the left side and right side of the transverse beam 26 and 28make the centers of the left side and right side transverse beam endposts and balls 30 and 32 align with the plan view centerline 17 of thetransverse beam.

When a human is running, the femur sockets at the right and left ends ofthe pelvic bone gyrate in a way that causes the pelvic bone's horizontalaxis to outline a horizontally oriented point to point double vortexwith the adjoined points coming together at the base of the spine. Thefemur sockets themselves outline forward rolling circles which are thebases of the cone shaped vortices. This pelvic action drives the femursin a reciprocating motion reminiscent of the reverse of the action ofthe steam pistons of an old fashioned locomotive driving its drivingwheels, with the additional complexity that the knee ends of the femursaren't fixed, as are the ends of steam pistons, but are themselvesmoving in their own forward rolling circles.

The structure we have described supports part of the weight of therider's body while it permits the unrestrained natural running action ofthe pelvis. This three-dimensional articulation is illustrated asdeconstructed into three two-dimensional views in FIGS. 18, 19, and 20.

The double vortex gyration of the structure, in sympathy with thepelvis, when seen in two dimensions from above in plan view in FIG. 18appears, as shown by double ended arrows, as a reciprocating, (rightside forward, left side aft, then left side forward right side aft)partial rotation around the center point of the transverse beam, whichpoint corresponds to the pivot point of the pelvis at the base of thespine. The right and left rotational arrows indicate the resultingturning of the pedals.

The structure in side elevation view, FIG. 19, shows a horizontal foreand aft double headed arrow indicating the same reciprocating action asthe arrows in FIG. 18, with the addition of a vertical double headedarrow indicating the simultaneous rocking side to side of the transversebeam, right side higher, left side lower, then left side higher, rightside lower. In combination, these motions allow for the forward rollingcircular motion common to the human femur sockets of the pelvis and theright and left ends of the transverse beam, as indicated by therotational arrow. Again, the lower rotational arrow indicates theturning of the pedals.

The structure in rear elevation view, FIG. 20, shows vertical doubleheaded arrows indicating the side to side rocking of the transversebeam. In this two-dimensional view the pedals also appear, as indicatedby double headed arrows, to be moving in an up and down reciprocatingaction. However when the information illustrated in all threetwo-dimensional views is combined, the correct idea of the pedals movingin forward rolling circles 180 degrees out of phase with each otheremerges, as does the correct idea of the seat structure's transversebeam gyrating around a central pivot with its ends moving in forwardrolling circles 180 degrees out of phase with each other.

In FIGS. 21, 22, and 23, three-dimensional information is againdeconstructed into three two-dimensional views. Each view shows a doubleheaded arrow passing through the base of the spine and the left andright ischeal tubularities and the left and right femur sockets of thepelvic bone. These arrows represent what is called above the horizontalaxis of the pelvis. As shown, this axis is parallel to the transversebeam of the seat structure, and maintains this parallel relationshipthroughout the pedaling cycle. Through the pedaling cycle, the lowersurface of the buttocks, the skin and muscle covering the rider'sischeal tubularities, which is the surface bearing the rider's weight,is continuously changing its tilt from nearly level to a forward cantand back again as the pelvis gyrates. The buttock supporting seat partsof this structure, whose mounts allow them to tilt in any direction androtate independently from the transverse beam on whose ends they aremounted, maintain constant contact with the lower surfaces of thebuttocks and tilt and rotate relative to the transverse beam exactly insympathy with the buttocks throughout the pedaling cycle, and thus donot rub against them. Therefore no friction is created between therider's skin and this structure.

As illustrated in FIGS. 21, 22, and 23, during a pedaling cycle, thestructure that we have described permits free motion of the body in anunrestrained way much like the motion of the body during running. Duringthe pedaling cycle, the ischial tubularities of the pelvic bone need tomove independently of one another. For example, their vertical positionsrelative to one another changing continually from the left side of thepelvic bone being higher than the right side, the two sides being at thesame elevation, to the right side being higher than the left side, andback through the same elevation, returning to the left side being higherthan the right. During the pedaling cycle, there is cyclical fore andaft motion of the two sides of the pelvis. The motion varies from theleft side of the pelvis being forward of the right side through the leftside and right side being at the same positions fore and aft through theright side being forward of the left side and back through being in thesame positions fore and aft and then with the left side forward of theright side again. Also, during each pedaling cycle, the canting of eachof the femurs, and therefore the skin of the buttocks and the bottoms ofthe thighs vary cyclically. For each leg, the angle of the femur variesfrom being approximately horizontal to being canted down in the frontrelative to the back of the femur and then returning to theapproximately horizontal position. These three cyclical motions—the leftand right sides of the pelvis moving up and down relative to oneanother, the left and right sides of the pelvis moving fore and aftrelative to one another, and each of the femurs canting up and downitself and in an opposite sense from the canting up and down of theother femur—all occur simultaneously through the pedaling cycle, makingfor a complex gyrating motion. The mountings of the seat parts on thetransverse beam and of the transverse beam on the seat post of thebicycle and the freely permitted motion of them assures that the pelvicand femur cyclical motions are accommodated freely, without resistance,and without friction between the seat parts and the buttocks and thighs.

This complex motion is also illustrated in FIG. 24. When the pedal is attwo o'clock (the first line of cells in FIG. 24) the right pelvis (wesometimes use the word pelvis interchangeably with the word buttocks;what were referred to as the pelvises are also sometimes referred to asischial tubularities of the pelvis; sometimes, when we refer tobuttocks, we are also referring to the muscle and skin that covers theischial tubularities) is forward of the left pelvis, the right pelvis ishigher than the left pelvis, the right femur is approximatelyhorizontal, and the left is canted downward. When the pedal is at fiveo'clock, the right pelvis is slightly forward of the left pelvis and isslightly lower than the left pelvis, and the right femur is canted downwhile the left femur is approximately horizontal. When the pedal is ateight o'clock, the left pelvis is forward of and higher than the rightpelvis, and the right femur is canted down slightly and the left femuris canted up slightly. When the pedal is at 11 o'clock, the right femuris slightly behind and higher than the left femur, the left femur iscanted down, and the right femur is approximately horizontal. One coulddescribe this motion during the pedaling cycle as the left pelvis andthe right pelvis following roughly circular gyrating paths around thepoint at which the center of the transverse beam is mounted on the ball.The two gyrating paths are in a 180° phase relationship to one another.The cants of the femurs are also oscillating in opposite phases, up anddown.

A wide variety of other configurations of the parts in their assemblyare also possible alternatively or in combination with the onesdescribed above.

In some examples, as shown in FIGS. 25, 26, and 27, a cylindrical shaft110, seen vertical in front elevation, leans toward the rear of thebicycle to the same degree as the bicycle's own seat post in sideelevation, and has a diameter that fits into the seat post so that itsheight can be held in proper adjustment by the bicycle's own seat postclamp. The upper end of the shaft connects to a horizontal beam 112,which cantilevers toward the rear of the bicycle and extends far enoughto position the rider a comfortable distance from the handlebars. Thecantilevered beam connects to the upper end of the shaft and cantileverstoward the rear of the bicycle 3″ (Q₁), for example, from the centerlineof the shaft to the center of the opening 115 of the block 114. The beammay be made of the same material as the shaft and rigid, or it may bemade of a material which is stiff enough to adequately support the riderwhile springy enough to provide a shock absorbing suspension.

The rear end of the beam supports and is fastened to a block 114, asshown in FIGS. 28, 29, and 30, which is taller than long and longer thanwide, and which is perforated transversely by an opening 115 which istaller than wide and whose edges are rounded in both side elevation andplan view, such that it accommodates a transverse beam that includes twosides 116 and 118, as shown in FIGS. 25, 26, and 27, in a way thatallows the beam to gyrate in the opening to a degree which allows therider all desired mobility, but doesn't allow the beam to tip toward thefront or rear of the bicycle. Block 114 measures 2½″ high (M), 1⅝″ long(N), and ⅝″ wide (O), and is perforated by opening 115 which measures1⅞″ high (P) by ⅝″ wide (Q), for example. The transverse beam 116 and118, as shown in FIGS. 34 and 35, is made of two flat pieces which, whenbolted together, fit through the hole in the perforated block 114, withenough clearance to allow the beam to gyrate with slightly more than themaximum gyration required by the rider's pelvis in pedaling. The twoidentical flat transverse beam parts 116 and 118 measure ¼″ thick (R) by5½″ long (S), for example. At the ends which are attached to end postand ball elements 120 and 122, parts 116 and 118 measure 1″ high (T),which increases to 1½″ high (H) at a point ½″ from the end. This heightmeasurement extends 3¼″ toward the far end, at which point it againdecreases to 1″ height for the rest of its length, for example. The beamis held from sliding through the hole by cheek pieces 124, 126, 128, and130, as shown in FIGS. 31, 32, and 33, bolted to both sides by the samebolts which hold the beam elements together. The cheek pieces arerounded at their ends 125, 127, 129, 131 closest to the opening in bothfront and rear elevation views so that they don't interfere with thegyration action of the beam. Parts 124, 126, 128, 130 measure ¼″ thick(Y₁), 1¼″ high (Y₂), and 1½″ long (Y₃). Their ends, 125, 127, 129, 131,are shaped in elevation as ¾″ radius half circles (Z₁) and in plan as ¼″radius (Z₂) quarter circles. The beam elements terminate at theiroutside ends in posts 120 and 122, similar to those described in theearly are examples, but which require less offset to align them from endto end.

The transverse beam sides 116 and 118 are perforated with respectivelines of holes, similar to those described earlier, which are used inthe same way to adjust the length of the beam.

In some implementations, the rear end of the cantilevered beam supportsand is fastened to a short cylinder 216, which measures 1½″ diameter(W₁) and ½″ high (W₂), for example, as shown in FIGS. 37 and 38,perforated by a hole 217 at its center and by a circle of shallow holes219 around its circumference in which flexible solid rubber cylinders218, are inserted, and whose upper ends are fitted in matching shallowholes 219 in a matching short cylinder 220, with a similar centralperforation 221, placed on them upside down. The upper short cylindersupports and is fastened to a block 224, which is wider side to sidethan tall and taller than it is thick from front to back. Block 224measures 2½″ long (X₁), ½″ thick (X₂), and 1½″ high (X₃), for example.The block is perforated by a ¼″ diameter hole 225 which aligns with thecentral holes 223 in the two matching short cylinders 216 and 220. Thesame hole continues in line through to the bottom of the cantileveredbeam or spring. A Dacron cord 222, or other flexible line of anon-stretching material passes through all of these aligned holes and ispulled tight and held tight by knots 227 or other line stopping devicesat its ends, so that the rubber cylinders are held in compression. Therubber cylinders are of a length to allow clearance between the shortcylinders so that the block at the top can gyrate relative to thecantilevered beam. Flat transverse beam elements 228 and 230, are boltedto the top block in a way similar to those described earlier.

In some examples, the short cylinders of the third embodiment containbetween them a coiled spring 310, as shown in FIG. 36, which is attachedto each of them, similarly allowing the attached upper block to gyraterelative to the cantilevered beam, but obviating the need for a centraltension cord.

The ends of the transverse beams in various implementations may haveball and socket joints to connect them to the seat sections, as in thefirst examples that we described, or they may be attached to the seatsections with devices similar to the central transverse beam tocantilevered beam joining devices of the later examples, allowing theseat sections to gyrate relative to the ends of the transverse beams.

As shown in FIGS. 42 through 48, in some embodiments for mounting thetransverse beam, a post connector 312 and a beam connector 314 areassembled and held together by a cylindrical coiled spring 310 (anexample of a variety of possible compliant elements), which serves asboth a double-ended screw holding the connectors together and as aflexible universal joint allowing the connectors to rock relative to oneother. The beam connector 314 houses a cylindrical socket 324 and thepost connector 312 houses a corresponding cylindrical socket 318. Bothof the sockets are tapped by threads that match the helical shape andpitch of the coiled spring 310, thus allowing the coiled spring 310 tofunction as a screw fastening.

The post connector 312 has a cylindrical bottom part 313. The top ofpost connector 312 is a flat round flange or platform 320 on which abottom surface 321 of the beam connector can bear. The post 14 isinserted in a lower socket 316 of post connector 312, where it may befastened with adhesive or a set screw.

The beam connector 314 has two opposite flat surfaces 315, 317, arectangular upper part 326, and two semicircular rockers 322 that reston and are supported by the platform 320 and are free to rock side toside on the platform 320, because there is no attachment between thebeam connector 314 and the platform 320 other than the spring 310. Theflat upper portion 326 of the beam connector 314 functions as and formspart of the transverse beam in the same way as the rectangular splitblock 19 (as shown in FIG. 4). The side view of the assembly shown inFIG. 43 shows how the middle section 321 of the spring 310 is positionedbetween the rockers 322 and is free to bend.

This arrangement of the spring 310, the beam connector 314, and the postconnector 312 permits the axes 323 and 325 (defined by the axes of theholes that hold the upper and lower ends of the spring 310) to tilt orrock relative to one another while remaining engaged at the bottomsurface 321 of the beam connector and the top surface 327 of theplatform 320 (because of the compressive force of the spring tending topull the connectors together and the force of gravity), tilting withinthe plane of the paper of FIG. 42 is relatively easy and as the beamconnector 314 rocks within that plane relative to the post connector312, the semicircular bottom surface 321 rolls over the surface 327. Thefarther the beam connector rocks relative to the post connector, themore tension that is applied to the spring 312 and the greater therestoring force applied by the spring to cause the beam connector toreturn to its rest position (in which the axes of the two connectors arealigned). Conversely, rocking of the beam connector relative to the postconnector in the plane of the paper of FIG. 43 is more difficult (thoughnot impossible) because the bottom surfaces 329 of the beam connectorhave breadth and are flat. It is also possible to move the beamconnector vertically up relative to the post connector so that theservices are no longer bearing against one another, but this would notbe the typical motion because of the weight of the rider applied bygravity. Complex rocking of the axis of the beam connector relative tothe axis of the post connector in planes other than the planes of thepaper and FIGS. 42 and 43 would also be possible. In general, duringtypical use, most or all of the rocking is in the plane of the paper ofFIG. 42 and very little or none of it is in the plane of the paper ofFIG. 43.

The spring 310 stiff can be chosen to be just stiff enough to return thebeam connector to its upright position (with its axis aligned with theaxis of the post connector) when someone on the seat gets off the seatand prevents rocking of the beam connector relative to the postconnector while the seat is not occupied. When the beam connector isreturned to this position, the transverse beam is in turn restored to aposition and orientation that is level and square relative to the planview longitudinal center line of the bicycle. This arrangement can makethe seat more inviting and physically easier for a user to mount. Thespring could be made stiffer than this minimum amount, but then it wouldtend to resist the free motion of the users pelvis and legsunnecessarily and therefore waste energy. The stiffness of the spring310 supplement the effect of the shape of the bottom surfaces of therockers 322 in resisting fore and aft rocking. A wide variety ofexisting or custom made springs can be used, chosen to be suitable for agiven application. As an example, a compression spring typically used tohold the blade of a woodworking band saw could be used for a bicycleapplication. An example of such a spring is formed of coiled highstrength ⅛″ square stock chrome-vanadium alloy that is wound to have ⅛″spaces between successive turns so that 1″ of spring length has fourcoils and four spaces. The ends of the spring, which are sometimesmilled flat for the band saw application, can be cut off for the bicycleapplication to enable the spring to the used as a screw. Although such aspring may be stiffer than necessary, the leverage of the transversebeam is great enough and the changes in the beam's angle relative to thebicycle frame are small enough that such a spring does not provide muchresistance when in use, and returns the seat to its normal positionafeter the rider gets off the bicycle. FIG. 46 shows a version of theportion of the seat support of FIG. 8 which is modified to fit into thesocket 316. The central ball joint 16 has been eliminated and thevertical post 14 lengthened to fit in the socket 316 with a height of ¾″(A4).

FIG. 44 shows a vertical section through the post connector 312 whileFIG. 45 shows a top view of the post connector 312. In a specificexample, The diameter of platform the 320 is 2⅜″ (E2), and the diameterof the post connector 312 is 1⅜″ (E3), while the inner threaded diameterof the socket 318 measures ¾″ (E4). The height of the platform 320 is ⅜″(E5), while the distance from the top of the platform 320 to the bottomof the socket 318 is ¾″ (E6) and the depth of the socket 316 is ¾″ (E7),and the connector post 312 is 1¾″ (E8) high.

In some examples, as shown in FIGS. 47 and 48, the flat upper portion326 of the beam connectors 314 is 2¾″ (E8) while the maximum width ofthe rockers 322 is 2″ (F3). The flat upper portion 326 is 1½″ (F4) hi,while the overall height of the part 313 measures 2½″ (F5). The socket324 is ¾″ (F8). The beam connector 314 is a split part, with the twohalves being identical. Each half has a width of ¾″ (F6) at its uppersurface and each rocker 322 has a width of 5/16″ (F7).

A wide variety of other implementations would be possible. The springcould be replaced by other kinds of compliant elements and combinationsof them. The bearing surfaces between the connectors can be configureddifferently. The way of mounting the compliance elements in the twoconnectors could be varied. We use the term connector very broadly toinclude any sort of connecting device.

Although the examples discussed above are of seats for bicycles, similarseats can be mounted in similar ways on any of a wide variety of otherdevices on which people sit. Such devices can include cycling devices inwhich the buttocks and legs move cyclically in a motion that is similarto or akin to the motion that occurs during running. Such cyclingdevices can include bicycles, unicycles, tricycles, and human poweredaircraft, to name a few. The cycling devices can include devicesdesigned to move the entire user from one place to another, and devicesin which the user remains in the same place while the cyclical motion isoccurring, such as a wide variety of exercise devices. Furthermore,devices that have seats and in which the user's buttocks and legs aremoving continually or only from time to time and are not necessarilymoving cyclically can benefit from the concepts that we have discussed,for example, seats in trucks or boats or other vehicles, office and workchairs, and other kinds of chairs. Other implementations are also withinthe scope of the following claims.

The invention claimed is:
 1. An apparatus comprising a seat on which auser of a device is to sit while pedaling, the seat including a rigidtransverse beam that is to lie parallel to an axis that passes throughthe femur sockets of the pelvic bone of the user as pedaling of the usersitting on the seat causes the axis to yaw and roll relative to thedevice, the transverse beam having a central axis that extends laterallyrelative to the direction in which the user faces while on the seat andpedaling, and a coupling element configured to be located verticallybelow the central axis of the transverse beam when the user is on theseat and pedaling, to couple the rigid transverse beam to a frame of thedevice, and by operation of the coupling element to enable simultaneousyawing and rolling motion of the rigid transverse beam about thecoupling element in synchrony with the axis that passes through thefemur sockets as the user is on the seat and pedaling.
 2. The apparatusof claim 1 in which the coupling element comprises a spring.
 3. Theapparatus of claim 1 in which the coupling element comprises a helicallywound spring.
 4. The apparatus of claim 1 in which the coupling elementcomprises rubber cylinders.
 5. The apparatus of claim 1 in which thecoupling element is configured to be attached to connectors associatedrespectively with the seat and with the frame.
 6. The apparatus of claim1 comprising a connector associated with the seat and configured toreceive a portion of the coupling element.
 7. The apparatus of claim 1comprising a connector associated with the frame and configured toreceive a portion of the coupling element.
 8. An apparatus comprising aspring having a helical winding aligned along an axis, the spring beingconfigured to attach a frame of a device to be pedaled to a seat onwhich a user is to sit when pedaling the device, there being no otherattachment between the frame of the device and the seat other than thespring, a threaded hole in the seat, and a threaded hole in the frame ofthe device, the helical winding of the spring matching the threadedholes in the seat and the frame to attach one end of the helical windingto the threaded hole in the seat and an opposite end of the helicalwinding to the threaded hole in the frame of the device so that the seatcan be tilted relative to the frame by bending the helical windingtransversely to the axis at a location between the two ends.
 9. Theapparatus of claim 8 in which the spring is linear and wound.
 10. Theapparatus of claim 8 comprising a connector that includes the threadedhole associated with the seat.
 11. The apparatus of claim 8 comprising aconnector that includes the threaded hole associated with the frame. 12.An apparatus comprising a bearing structure between a frame of a deviceand a seat on which a user sits when pedaling on the device, the bearingstructure comprising a first bearing surface on the frame, a secondbearing surface on the seat, the second bearing surface in contact withand rolling across the first bearing surface at a bearing interface whenthe user is pedaling, and a helically wound spring that extends throughthe first bearing surface, then through the bearing interface, and thenthrough the second bearing surface, and is attached to the seat on oneside of the bearing interface and to the frame on the other side of thebearing interface, and thereby attaches the seat to the frame, theportion of the helically wound spring that extends through the bearinginterface being compliant, the attachment of the helically wound springto one or both of the seat or the frame comprising a threading of thehelically wound spring onto a threaded receiving element.
 13. Theapparatus of claim 12 in which the helically wound spring is compliantand tends to return the seat to a resting upright position relative to aframe when the user is not on the device, or comprises a compliantelement that tends to return the seat to a resting upright positionrelative to the frame when the user is not on the device.
 14. Theapparatus of claim 1 in which the coupling element comprises a resilientelement.
 15. The apparatus of claim 1 in which the coupling element isfor returning the seat to a substantially horizontal plane when the useris not on the seat.